2022-04-21 19:21:00

by Luis Chamberlain

[permalink] [raw]
Subject: Re: [PATCH modules-next 1/1] kallsyms: enhance %pS/s/b printing when KALLSYSMS is disabled

On Thu, Apr 21, 2022 at 09:45:42AM +0530, Maninder Singh wrote:
> print module information when KALLSYMS is disabled.
>
> init_build_id() function is moved to module/main.c as it can be
> independent of kallsyms.
>
> No change for %pB, as it needs to know symbol name to adjust address
> value which can't be done without KALLSYMS.
>
> (A) original output with KALLSYMS:
> [8.842129] ps function_1 [crash]
> [8.842735] pS function_1+0x4/0x2c [crash]
> [8.842890] pSb function_1+0x4/0x2c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3]
> [8.843175] pB function_1+0x4/0x2c [crash]
> [8.843362] pBb function_1+0x4/0x2c [crash b367e79021b9f3b0172f9a36d4261c1f528ca1b3]
>
> (B) original output without KALLSYMS:
> [12.487424] ps 0xffff800000eb008c
> [12.487598] pS 0xffff800000eb008c
> [12.487723] pSb 0xffff800000eb008c
> [12.487850] pB 0xffff800000eb008c
> [12.487967] pBb 0xffff800000eb008c
>
> (C) With patched kernel
> with KALLYSMS:
> [41.974576] ps function_1 [crash]
> [41.975173] pS function_1+0x4/0x2c [crash]
> [41.975386] pSb function_1+0x4/0x2c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
> [41.975879] pB function_1+0x4/0x2c [crash]
> [41.976076] pBb function_1+0x4/0x2c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
>
> without KALLSYMS:
> [9.624152] ps 0xffff800001bd008c [crash] // similar to original, no changes
> [9.624548] pS 0x(____ptrval____)+0x8c [crash] // base address hashed and offset is without hash
> [9.624847] pSb 0x(____ptrval____)+0x8c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
> [9.625388] pB 0x(____ptrval____)+0x8c [crash]
> [9.625594] pBb 0x(____ptrval____)+0x8c [crash a8b20caaec9635b316cf4812f6b55598fe2b7cee]
>
> with disable hashing:
> [8.563916] ps 0xffff800000f2008c [crash]
> [8.564574] pS 0xffff800000f20000+0x8c [crash]
> [8.564749] pSb 0xffff800000f20000+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca]
> [8.565008] pB 0xffff800000f20000+0x8c [crash]
> [8.565154] pBb 0xffff800000f20000+0x8c [crash 3423a8993a7033fb79e5add14bf9d8d6b56330ca]
>
> Suggested-by: Petr Mladek <[email protected]>
> Co-developed-by: Vaneet Narang <[email protected]>
> Signed-off-by: Vaneet Narang <[email protected]>
> Signed-off-by: Maninder Singh <[email protected]>
> Reviewed-by: Petr Mladek <[email protected]>
> Tested-by: Petr Mladek <[email protected]>

Thanks! Queued onto modules-testing. If there are no complaints from the
build I'll move this to modules-next.

Luis